1. Technical Field
The present disclosure relates to a powder transport device and an image forming apparatus such as a copier, facsimile machine, or printer incorporating the powder transport device.
2. Description of the Related Art
Image forming apparatuses that form toner images using toner in the form of powder are widely known. In electrophotographic-type image forming apparatuses, for example, toner is selectively attracted onto a latent image formed on a surface of a latent image carrier. In another example, in direct writing-type image forming apparatuses, dot-shaped toner groups scattered from a toner-flying device is directly attracted onto a recording medium and an intermediate transfer body. In both types, the used toner (transfer-residual toner and scattered toner) that could not make a contribution to the formation of the toner image cannot but come out of the latent image carrier and the toner-flying device. In general, this residual toner is collected by a cleaning device and then transported to a toner collection container by a toner transport device for disposal or reuse.
As image forming apparatuses become more compact and colorized, the configuration of the toner transport device tends to be more complicated. For example, in an image forming apparatus proposed in JP-2005-338163-A, it is only necessary to provide a single transport tube to transport the transfer-residual toner collected from the surface of the photoreceptor as the latent image carrier to the toner collection container because only a single latent image carrier is provided therein.
By contrast, some multiple-color image forming apparatuses that form color images include four photoreceptors to form separate toner images of the colors yellow, magenta, cyan, and black, individually. In this type of multiple-color image forming apparatus, it is necessary to provide four transport tubes to collect the transfer-residual toner from the four photoreceptors, thereby complicating the configuration of the toner transport device. In general, the more complicated the configuration of the toner transport device, the greater the susceptibility of the toner transport device to clogging.